ActiveSupport::Cache::FileStoreを使ったリクエストラッパーのサンプル

my_tumblr.rb

# -*- coding: utf-8 -*-
require 'rubygems'
require 'active_support/core_ext/numeric/time'
require 'active_support/cache'
require 'addressable/template'
require 'net/http'
require 'xmlsimple'

module MyTumblr
  extend self

  ApiRead = Addressable::Template.new 'http://{user}.tumblr.com/api/read'  

  def api_read(user, params = {})
    url = ApiRead.expand :user => user
    parse_response url, params
  end

  private

  def parse_response(url, params)
    url.query_values = params
    body = get_url url
    XmlSimple.xml_in body
  end
  
  def get_url(url)
    response = Net::HTTP.start(url.host, url.port) do |http|
      http.get url.request_uri
    end

    if Net::HTTPSuccess === response
      response.body
    else
      response.error!
    end
  end

  module Cache
    extend MyTumblr

    class << self
      attr_accessor :cache
      
      def setup(cache_dir, options = {})
        options.update({
          :namespace => 'my_tumblr'
        })
        self.cache = ActiveSupport::Cache::FileStore.new(cache_dir, options)
      end

      private
      
      def get_url(url)
        cache.fetch(url.to_s) { super }
      end
    end

  end
  
end

if __FILE__ == $0

  # リクエストを投げる
  data = MyTumblr::api_read('mitukiii')

  # キャッシュを5分有効にする
  MyTumblr::Cache::setup(ENV['TMPDIR'], {:expires_in => 5.minutes})

  # キャッシュされたデータがあればそれを返し
  # なければリクエストを投げる
  MyTumblr::Cache::api_read('mitukiii')
  MyTumblr::Cache::api_read('mitukiii')

end